Recently, a conference is held while connecting a plurality of bases to a network, and the conference is called an electronic conference. In the electronic conference, a conference can be held among users at the respective bases while displaying images (content) common to screens of the information processing apparatuses provided in each base. For example, it is possible to hold the conference between the plurality of bases while displaying attaching an image such as an electronic tag or a photograph on the content, or displaying characters written on the content by considering the screen as electronic imitation paper. Japanese Laid-open Patent Publication No. 2015-090607, Japanese Laid-open Patent Publication No. 2016-134846, and Japanese Laid-open Patent Publication No. 2013-65125 are disclosed as related arts.
While the electronic conference is being held, common content is displayed on the screen of the information processing apparatus at each base, and information is shared between the bases. However, since the screens of the information processing apparatuses at the respective bases are often not the same in a screen size and resolution, and are controlled independently of each other, a state may occur in which a part of the content is not displayed on the screen of a certain information processing apparatus. Meanwhile, as the electronic conference progresses, the content is operated by one of the bases and is updated at any time. Accordingly, for example, in a case where a part of the content that is not displayed on the screen of the information processing apparatus at the main base is operated by the information processing apparatus at the sub base, the main base may not notice the operation. In consideration of the above, it is preferable that the sub base can grasp the content of the operation performed by one base with respect to the common content in real time so as to smoothly progress the electronic conference.